Linux kernel mirror (for testing)
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1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef __SHMEM_FS_H
3#define __SHMEM_FS_H
4
5#include <linux/file.h>
6#include <linux/swap.h>
7#include <linux/mempolicy.h>
8#include <linux/pagemap.h>
9#include <linux/percpu_counter.h>
10#include <linux/xattr.h>
11#include <linux/fs_parser.h>
12
13/* inode in-kernel data */
14
15struct shmem_inode_info {
16 spinlock_t lock;
17 unsigned int seals; /* shmem seals */
18 unsigned long flags;
19 unsigned long alloced; /* data pages alloced to file */
20 unsigned long swapped; /* subtotal assigned to swap */
21 struct list_head shrinklist; /* shrinkable hpage inodes */
22 struct list_head swaplist; /* chain of maybes on swap */
23 struct shared_policy policy; /* NUMA memory alloc policy */
24 struct simple_xattrs xattrs; /* list of xattrs */
25 atomic_t stop_eviction; /* hold when working on inode */
26 struct inode vfs_inode;
27};
28
29struct shmem_sb_info {
30 unsigned long max_blocks; /* How many blocks are allowed */
31 struct percpu_counter used_blocks; /* How many are allocated */
32 unsigned long max_inodes; /* How many inodes are allowed */
33 unsigned long free_inodes; /* How many are left for allocation */
34 spinlock_t stat_lock; /* Serialize shmem_sb_info changes */
35 umode_t mode; /* Mount mode for root directory */
36 unsigned char huge; /* Whether to try for hugepages */
37 kuid_t uid; /* Mount uid for root directory */
38 kgid_t gid; /* Mount gid for root directory */
39 bool full_inums; /* If i_ino should be uint or ino_t */
40 ino_t next_ino; /* The next per-sb inode number to use */
41 ino_t __percpu *ino_batch; /* The next per-cpu inode number to use */
42 struct mempolicy *mpol; /* default memory policy for mappings */
43 spinlock_t shrinklist_lock; /* Protects shrinklist */
44 struct list_head shrinklist; /* List of shinkable inodes */
45 unsigned long shrinklist_len; /* Length of shrinklist */
46};
47
48static inline struct shmem_inode_info *SHMEM_I(struct inode *inode)
49{
50 return container_of(inode, struct shmem_inode_info, vfs_inode);
51}
52
53/*
54 * Functions in mm/shmem.c called directly from elsewhere:
55 */
56extern const struct fs_parameter_spec shmem_fs_parameters[];
57extern int shmem_init(void);
58extern int shmem_init_fs_context(struct fs_context *fc);
59extern struct file *shmem_file_setup(const char *name,
60 loff_t size, unsigned long flags);
61extern struct file *shmem_kernel_file_setup(const char *name, loff_t size,
62 unsigned long flags);
63extern struct file *shmem_file_setup_with_mnt(struct vfsmount *mnt,
64 const char *name, loff_t size, unsigned long flags);
65extern int shmem_zero_setup(struct vm_area_struct *);
66extern unsigned long shmem_get_unmapped_area(struct file *, unsigned long addr,
67 unsigned long len, unsigned long pgoff, unsigned long flags);
68extern int shmem_lock(struct file *file, int lock, struct user_struct *user);
69#ifdef CONFIG_SHMEM
70extern const struct address_space_operations shmem_aops;
71static inline bool shmem_mapping(struct address_space *mapping)
72{
73 return mapping->a_ops == &shmem_aops;
74}
75#else
76static inline bool shmem_mapping(struct address_space *mapping)
77{
78 return false;
79}
80#endif /* CONFIG_SHMEM */
81extern void shmem_unlock_mapping(struct address_space *mapping);
82extern struct page *shmem_read_mapping_page_gfp(struct address_space *mapping,
83 pgoff_t index, gfp_t gfp_mask);
84extern void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end);
85extern int shmem_unuse(unsigned int type, bool frontswap,
86 unsigned long *fs_pages_to_unuse);
87
88extern bool shmem_huge_enabled(struct vm_area_struct *vma);
89extern unsigned long shmem_swap_usage(struct vm_area_struct *vma);
90extern unsigned long shmem_partial_swap_usage(struct address_space *mapping,
91 pgoff_t start, pgoff_t end);
92
93/* Flag allocation requirements to shmem_getpage */
94enum sgp_type {
95 SGP_READ, /* don't exceed i_size, don't allocate page */
96 SGP_CACHE, /* don't exceed i_size, may allocate page */
97 SGP_NOHUGE, /* like SGP_CACHE, but no huge pages */
98 SGP_HUGE, /* like SGP_CACHE, huge pages preferred */
99 SGP_WRITE, /* may exceed i_size, may allocate !Uptodate page */
100 SGP_FALLOC, /* like SGP_WRITE, but make existing page Uptodate */
101};
102
103extern int shmem_getpage(struct inode *inode, pgoff_t index,
104 struct page **pagep, enum sgp_type sgp);
105
106static inline struct page *shmem_read_mapping_page(
107 struct address_space *mapping, pgoff_t index)
108{
109 return shmem_read_mapping_page_gfp(mapping, index,
110 mapping_gfp_mask(mapping));
111}
112
113static inline bool shmem_file(struct file *file)
114{
115 if (!IS_ENABLED(CONFIG_SHMEM))
116 return false;
117 if (!file || !file->f_mapping)
118 return false;
119 return shmem_mapping(file->f_mapping);
120}
121
122extern bool shmem_charge(struct inode *inode, long pages);
123extern void shmem_uncharge(struct inode *inode, long pages);
124
125#ifdef CONFIG_SHMEM
126extern int shmem_mcopy_atomic_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd,
127 struct vm_area_struct *dst_vma,
128 unsigned long dst_addr,
129 unsigned long src_addr,
130 struct page **pagep);
131extern int shmem_mfill_zeropage_pte(struct mm_struct *dst_mm,
132 pmd_t *dst_pmd,
133 struct vm_area_struct *dst_vma,
134 unsigned long dst_addr);
135#else
136#define shmem_mcopy_atomic_pte(dst_mm, dst_pte, dst_vma, dst_addr, \
137 src_addr, pagep) ({ BUG(); 0; })
138#define shmem_mfill_zeropage_pte(dst_mm, dst_pmd, dst_vma, \
139 dst_addr) ({ BUG(); 0; })
140#endif
141
142#endif